12 Days of Christmas GMAT Competition - Day 7: In a meta-analysis of s

Question

12 Days of Christmas GMAT Competition with Lots of Fun

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.

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V33-08

AndrewN · Accepted Answer

OFFICIAL EXPLANATION

Taking a look at the question stem, we can see that we are aiming to resolve a paradox. But be careful: do  not  assume that the paradox that needs to be addressed is the one and only paradox, or you might shift into territory that can be detrimental to your CR success.

Believe it or not, we are dealing with just two sentences here. The first outlines that studies were conducted to  identify relationships between cardiovascular health and cholesterol levels , and two variables proved most statistically significant in  decreasing the incidence of major cardiovascular events : 1)  high serum HDL cholesterol levels  and 2)  a high HDL-to-LDL ratio .

The second sentence tells us that a certain group of study participants,  those who consumed no animal products and thus no dietary cholesterol , had the opposite of what was deemed most desirable in sentence one,  the lowest HDL cholesterol levels  and  low HDL-to-LDL ratios , but this group had a significantly  lower incidence of any major cardiovascular event  compared to all other groups.

There are two logical directions in which this paradox could go. We either want to know  what caused  the no-animal-product group (hereafter referred to as NAP) to suffer from the fewest cardiac events, comparatively, or we want to know  how  that same group was able to enjoy health benefits that would fall more in line with participants who had high serum HDL cholesterol and high HDL-to-LDL ratios.

I hope that by now, three CR questions into this challenge, you have developed a keen eye for what is a premise, and you have to remember, attacking a premise should not be your goal in nearly all types of CR questions. (A  weaken the force of the evidence  question can be thought of as an exception.) In this case, if the subset of participants in question has met a standard for statistical significance, then if anything, the findings about this group should warrant further study and consideration, not a dismissal.  Red light .

This is an interesting fact, but  the human body  refers to  all  bodies, those that either ingest animal products or do not, so we still gain no insight into why the two groups of participants, with different markers for cholesterol, achieved similar cardiovascular benefits. This answer choice touches on the right notes, but it is a blind alley, too broad in scope.  Red light .

Although this does  not  resolve one of our two likely paradoxes—we still have no idea why the NAP group enjoys the same cardiovascular benefits as the group with the highest statistical significance—it does shed light on why the NAP group would have low HDL cholesterol levels and a lower HDL-to-LDL ratio. There appears to be some unknown mechanism or correlation besides high serum HDL cholesterol that is providing protection for the NAP participants in the studies. Keep this one for now and look to disprove other answer choices.  Green light .

This one seems easier to target after those first three. We have a double weakener in  some  and  not all . The studies do not need to have been conducted in a vacuum to produce valid findings, and, of course, we have no notion of just how many studies  some  may be referring to. Let out a sigh of relief and keep moving.  Red light .

This answer choice runs in the same vein (sorry, I told you I like puns) as (A), actually. You should  hope  to get these sorts of options when you hit a more challenging CR question. Again, we are meant to doubt the validity of the studies, a distraction that keeps us from doing what we are asked to do: resolve the conflicting findings of those studies. We cannot resolve anything if we toss out all the data.  Red light .

There you have it. Another question done and dusted. I feel the need to reiterate that you should not pursue a solution to a CR question blinded by what you think  must be  the one and only answer to the question. Here, it is perfectly reasonable to look for an answer to the question,  What causes the NAP group to get even better results than the other group?  But the passage and answer choices provide no insights into the matter. However, one answer choice does provide an explanation that allows us to appreciate why the NAP group had a lower level of a statistically significant factor, and that is the answer we should get behind.

- Andrew

Deepakjhamb · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.

Solution : answer is (C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.

discrepancy or paradox is that while high levels of HDL & HDL to HDL ratio lead to better cardio vascular health , it has been
found that ppl who do not take animal products or dietery cholestrol have low HDL but still have better cardio vascular health

so by far pre-thinking is that something in animal products leads to blocking the arteries for which High HDL level is required which is clearly explained by option c ) that HDL is required in high quantities only when animal fat related molecules block the arteries but in other cases where animal diet or dietery cholestorol is not taken HDL in low quantities may also be sufficient for good cardio health

a) totally out of scope

b)does not help explain paradox as it works for both type of diets animal and veg both

d) says that some results not accurately reported - but that is for both types of studies with animal and non-animal so not significant

e)methods for measuring cholestrol have no significance and are out of scope since this would apply to both animal and non-animal diet cholestrol studies so ruled out

Kinshook · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance. 
The statement does not help to resolve the conflicting findings of the meta-analysis. Incorrect

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol. 
Even when the human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol, the subset of study participants, those who consumed no animal products and thus no dietary cholesterol  had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios . This does not help to resolve the conflicting findings of the meta-analysis. Incorrect

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products. 
Since the subset of study participants who consumed no animal products and had no fat molecules derived from animal products did not need HDL cholesterol for removal of fat molecules out of artery walls, had low HDL cholesterol levels and low HDL-to-LDL ratios yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants. Correct

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed. 
The statement does not help resolve the conflict. Incorrect

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures. 
The statement does not help resolve the conflict. Incorrect

IMO C

DJ2911 · Answer

Correct Answer: C

Question Type:  Resolve the conflict
 The main conflict in the question:  A group of non-animal eaters had low HDL cholesterol and low HDL/LDL ratio and yet low cardio event than ANY other group.
 Pre-Thinking:  The Correct answer might in some way give a reason for low HDL and low ratio being safe in the given group.

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.
 Incorrect:   The small size of the group in no way tells us how low ratio and low HDL can lead to low risk.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.
 Incorrect:  This is a piece of generic information and in no way has any bearing on the conflict resolution.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.
 Correct:   HDL necessary for removal of only animal fat molecule. If someone doesn't eat animals, then having low HDL or a low ratio will have no risk for the individual. Thus this definitely helps resolve the conflict.

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.
 Incorrect:   The research is based on the results measured and not by what participants reported. Thus no bearing on the conflict

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
 Incorrect:   The conflict is that a subgroup in the current study is at lower risk then other current subgroups. What happened earlier gives no solution for the mentioned conflict.

ananya3 · Answer

P1: Researches did a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels
P2: They found the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. \
P3: After adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios
P4: yet the non-dairy participants suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Resolve the paradox pre-think - high level of HDL and HDL:LDL ration needed to avoid major cardiovascular event, but non-dairy participants with low levels has the lowest incidence of major cardiovascular event - non-diary provides something to avoid such events or non-diary miss something and therefore low levels is okay?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance. -  Incorrect 
Argument is concerned on why the non-dairy participant has lower incidences of major cardiovascular event and not with the actual number of the participants of any type

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol. -  Incorrect 
this does nothing to explain the paradox.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products. -   Correct  
if HDL cholesterol is necessary for the removal of fat molecules derived animal product is, this explains the paradox on why the low levels in non-diary participants is not a problem

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed. - Incorrect
Irrelevant to the argument. Though this may explain why some were exceptions from the assumption but not why a group of people with low level had lower number of events

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures. -  Incorrect 
Irrelevant. The argument is concerned to with why the conflicting points not how was the cholesterol measured

JanarthCj · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

This gives information about the subset of the total group but does not resolve the conflicting findings. So eliminate A.

If the human body is able to produce HDL & LDL, it does not explain the low level o0f HDL & HDL to LDL levels in the said subset. SO eliminate B.

HDL is necessary to maintain or increase cardiovascular function only when it is derived from animal products. Hence the subset of participants who do not consume animal products do not need HDL to maintain cardiovascular function. Thus explaining the relatively lower level of cardiovascular problems in spite of low HDL level & Low HDL to LDL ratio.

This is information does not help resolve the conflicting findings. So eliminate D.

Even if the measurement methods are refined, the apparent conflict in the argument is not resolved by this information. So eliminate E.

So the answer is C.

Nishant1795 · Answer

Option C states it correctly.

HDL cholesterol leads to increased cardiovascular function and HDL cholesterol is necessary when animal products are consumed. Hence the reason in the first line of the passage becomes true as more consumption of animal products will lead to higher HDL cholesterol and higher HDL-LDL Ratio. It also justifies the last line of the passage since there was no intake of animal products, there was no increase in cardiovascular function, HDL cholesterol was low and the HDL-LDL ratio was also low. Hence the cardiovascular events were low in frequency.

dushyanta · Answer

IMO  (C)

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on  decreasing the incidence of major cardiovascular events,  defined as hardening of the arteries, heart attacks, and strokes,  were high serum HDL cholesterol levels and a high HDL-to-LDL ratio.  The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those  who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.
 
Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.
 doesnt resolve the conflict still

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.
 but the anomaly subset had lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function,  only  when such molecules are derived from animal products.
 Ohh, so HDL cholestrol molecule from animal product was useful to decrease cardiovascular issues, but if it is not derived from animal product.. it doesnt matter..

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.
 very generic.. needs to point vegan people did not reported accurately

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
 very generic.. it doesnt even say methods for measuring serum chloestrol was incorrect..

Gmatfox · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

Pre-think :
Try to figure out the paradox:
A. high serum HDL cholesterol levels and a high HDL-to-LDL ratio --> low incidence of major cardiovascular (normal people)
B. the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios --> lower incidence of major cardiovascular events (people who consumed no animal products)

Question type: Resolve paradox 
--> Find a reason to see why both A and B happen. Notice the gap between A and B is that in B, people in the study do not consume animal products --> Any difference?

(A) The participants who consumed no animal products  represented one-tenth of the total number  of participants across all studies, just meeting the standard for statistical significance.
--> Paradox is still there. We want to solve the paradox even if the participants who consumed no animal products represented only a small fraction of the whole.

(B)  The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol. 
So we know participants who consumed no animal products represented still have HDL and LDL. But the paradox is still there because researchers are aware of that stuff. (They did calculate the level of HDL and the ratio of HDL to LDL)

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products. 
This is the correct answer. C helps us know that participants who consumed no animal products represented have less fat molecules derived from animal products than other participants, then have no need to have HDL cholesterol, and thus no increasing cardiovascular function, which may cause major cardiovascular events.

(D) Because of the duration of some of the studies,   not all participants accurately reporte d  what they consumed.
May be just one participant inaccurately reported what they consumed. D is not a strong evidence to solve the existing paradox.

(E)  Earlier studies , which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
We just focus on the so-called present procedures with the stated results. Paradox is still there.

dep · Answer

Study says high HDL and HDL/LDL is required for decreasing cardiovascular events
but a subset who consumed animal products had low HDL AND HDL/LDL but still low probability of cardiovascular event
because there might be something else which is in correlation to high HDL which increases risk of cardiovascular events

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol. - irrelevant

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products. - Correct - the high HDL may be body response to fat molecules in animal product which might increase cardiovascular event and may be the cause while in its absence high HDL and the ratio may not be required

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.- irrelevant

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures. - Irrelevant

vivek1408 · Answer

Answer is C IMO

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

Pre thinking: One research says high HDL/LDL ratio leads to decrease in cardiovascular diesease.
Another study of a group that did not eat animal products and subsequently had a low HDL/LDL ratio had very low incidence of cardiovascular diseases. A statement that says a high HDL/LDL ratio is not a necessary condition to have good cardio health could reconcile our paradox.

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.
 Just because the sample size of the second study is smaller, does not mean it is untrue. Eliminate.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.
 This option does provide some basis for why animal products need not be eaten to maintain good cardio health, but it does nothing to reconcile our paradox. Eliminate.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.
 Sounds good. If high HDL is needed by only those who eat animal products, then study participants who do not eat animal products need not necessarily have high HDL (or in other words a high HDL/LDL ratio) to have a good cardio health. This reconciles the paradox pretty good. 
 
(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.
 Could explain why study participants who ate no animal products could have good cardio health. But it doesnt reconcile our paradox. Eliminate

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
 Even the more refined procedures led to the same conclusion, that high HDL/LDL ratio was good for cardio health. Does not resolve the paradox. Eliminate.

Hence answer is C

vv65 · Answer

My answer is C

On a resolve the paradox question, it's always useful to state the paradox clearly. That's the recommended first step to tackle such questions.This question is fairly dense in terms of the amount of information packed in, so that first step is very important.

On the one hand, for most people: 
Cardiovascular health has a positive correlation with high serum HDL cholesterol levels and a high HDL-to-LDL ratio.

On the other hand, for one group of people (people who consume no animal products and thus no dietary cholesterol): 
They have the highest levels of cardiovascular and the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios

How can we explain this difference? Why is it that most people with good cardiovascular health have high HDL cholesterol but this group has the highest cardiovascular health and low HDL cholesterol?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.
- if the statistical significance was met, the group was large enough to draw conclusions 
- eliminate

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.
- does not explain why this group is different

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.
- this works
- tells us that people who consume animal products need HDL for better cardiovascular health; people who do not consume animal products do not need HDL cholesterol for high cardiovascular health

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.
- does not explain why this group is different

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
- does not explain why this group is different

Posted from my mobile device

rocky620 · Answer

We need to find out that even after having low HDL cholesterol & HDL-LDL ratios, why did not the chances of heart diseases decrease.

Prethinking:  Animal products/fats do something to reduce the chances.

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol  .....If at all it is just enhancing the conflict. Eliminate.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.  ...It is Out of scope. does nothing to the argument.Eliminate.

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.  ......We are not concerned with earlier studies, how they were conducted or what were the results. We are concerned with results of the present studies.Eliminate.

IMO option C

bidskamikaze · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.
-  Irrelevant.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.
-  This seems like a Trap. Though human body can produce all the cholesterol it needs to FUNCTION, it will still be more vulnerable to major cardiovascular problems, as low HDL cholesterol levels and relatively low HDL-to-LDL ratios should lead to more cardiovascular problems.

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.
 Correct. If HDL is needed only when animal products are consumed, then it seems plausible that participants who consumed no animal products and thus no dietary cholesterol suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants. After all, these participant don't need HDL as they don't consume animal products.

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.
-  "NOT ALL" can mean only one out of hundred, and so can be irrelevant.

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.
-  More refined methods do not imply that earlier results were wrong.

Answer C.

QuantMadeEasy · Answer

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.  The reason to resolve the conflict is not clear

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.  Correct

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.  The reason to resolve the conflict is not clear

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.

IMO C

winterschool · Answer

In a meta-analysis of several hundred studies designed to identify relationships between cardiovascular health and cholesterol levels, researchers found that the two most statistically significant variables on decreasing the incidence of major cardiovascular events, defined as hardening of the arteries, heart attacks, and strokes, were high serum HDL cholesterol levels and a high HDL-to-LDL ratio. The researchers also found, after adjusting for confounding variables such as smoking or exercise, that one subset of study participants, those who consumed no animal products and thus no dietary cholesterol, had the lowest HDL cholesterol levels and relatively low HDL-to-LDL ratios, yet suffered a markedly lower incidence of any major cardiovascular event than did any other subset of participants.

Which of the following, if true, most helps to resolve the conflicting findings of the meta-analysis?

(A) The participants who consumed no animal products represented one-tenth of the total number of participants across all studies, just meeting the standard for statistical significance.  Incorrect

it doesnt help to resolve argument

(B) The human body is capable of producing all the cholesterol it needs to function, both HDL and LDL, without any dietary cholesterol.  Incorrect

it can explain why high HDL cholesterol levels and low HDL cholesterol levels occur

(C) HDL cholesterol is necessary for the removal of fat molecules out of artery walls, thereby increasing cardiovascular function, only when such molecules are derived from animal products.  Correct

(D) Because of the duration of some of the studies, not all participants accurately reported what they consumed.  Irrelevant

(E) Earlier studies, which represented half of all the studies analyzed, incorporated methods for measuring serum cholesterol that were later replaced by more refined procedures.  Incorrect

not helpful

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